During the early development of the traffic signal housing, the major focus was the operational aspect, primarily a securement of lighting displays and a housing for electrical connections. The basic manufacturing and construction, materials, and specifically the structural and mechanical functions of traffic signals, have not been significantly changed or improved upon in approximately 65 years.
There are three basic structures that are commonly used to hold a traffic control signal located over or adjacent to a roadway travel lane and those structures include poles, steel mast arms, and load bearing cables strung between poles; the last being commonly referred to as span wire support systems. The three basic elements of a traffic control signal are one or more indicators (usually bulbs or LED modules); housings to secure the indicators (housings and indicators together are “signal heads” or a “signal face”); and the hardware used to hang the traffic control signals such as hangers, disconnect boxes, and cable attachment hardware.
Traffic signal hangers and housings have a known history of structural failures during hurricanes which sometimes result in injury and even fatalities due to uncontrolled roadway intersections. Traffic control signals, when designed as individual components, are very susceptible to damage from hurricane force winds, and multiple points of failure can occur in more than one specific component.
Prior art devices suffer from flawed design in which the housing of the electronics, known as the “disconnect box” and/or “disconnect hanger,” itself is used to support traffic signals by multiple linear load paths around the periphery of the disconnect box, rendering it susceptible to structural failures, especially at the disconnect box's cantilevered shelf areas during high wind events. In some instances, this disconnect box load path results in as much as 10-11 inches or more of horizontal load displacements through and around the periphery of the disconnect box, wherein the vertical loading of the traffic signal is transferred horizontally across the top of the disconnect box, then turns downward at each side of the disconnect box, then back along the bottom floor to an interrupted horizontal plane. An invention that eliminates many of the prior art deficiencies by changing the disconnect box's purpose from including structural loading of traffic signals to merely just the purpose of providing a weather proof housing for electrical components would be a significant improvement.